X-Ray Observation of the 2017 November Glitch in the Crab Pulsar

Zhang, Xinyuan; Peng, Shuai; Huang, Liangwei; Chen, Shaolong; Du, Y. J.

doi:10.3847/1538-4357/aade46

Cited by 15 publications

(26 citation statements)

References 13 publications

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“…Theν 0 of Zhang et al (2018) is an factor of two smaller than the value in Table 1. I believe these differences arise from the fact that firstly, the ν values listed by the JBCPME (from which Table 1 is derived) are themselves average values, mostly monthly averages, and secondly the preglitch durations of the three works may differ significantly; this may particularly affect the frequency second derivative. It is therefore concluded that there is broad agreement between the preglitch parameters derived here with those of Shaw et al (2018) and Zhang et al (2018), at least for the purpose of this work.…”

Section: Parametersupporting

confidence: 66%

“…Undertaking a similar exercise for the preglitch parameters of Zhang et al (2018), their ν 0 differs from the value in Table 1 above by −0.490 µHz; theirν 0 differs from the above value by −0.005 × 10 −12 Hz/sec. Theν 0 of Zhang et al (2018) is an factor of two smaller than the value in Table 1. I believe these differences arise from the fact that firstly, the ν values listed by the JBCPME (from which Table 1 is derived) are themselves average values, mostly monthly averages, and secondly the preglitch durations of the three works may differ significantly; this may particularly affect the frequency second derivative.…”

Section: Parametermentioning

confidence: 62%

“…The last observation available for this work was on 2019 Apr 26 (ObsID 2013010103, MJD 58599.988), but this had only 34 sec of live time. This kind of nonuniform cadence of observations implies that one can not perform the phase coherent timing analysis that was done by Shaw et al (2018) and Zhang et al (2018). This is particularly true for the glitch that is under discussion; it is so large that the change in phase over a single day can be larger than one cycle so that the cadence required for phase coherent analysis is several timing observations in a single day.…”

Section: Observations and Analysismentioning

confidence: 99%

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NICER observations of the Crab pulsar glitch of 2017 November

Vivekanand¹

2020

A&A

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Context. The Crab pulsar underwent its largest timing glitch on 2017 Nov 8. The event was discovered at radio wavelengths, and was followed at soft X-ray energies by observatories, such as XPNAV and NICER. Aims. This work aims to compare the glitch behavior at the two wavelengths mentioned above. Preliminary work in this regard has been done by the X-ray satellite XPNAV. NICER with its far superior sensitivity is expected to reveal much more detailed behavior.Methods. NICER has accumulated more than 301 kilo seconds of data on the Crab pulsar, equivalent to more than 3.3 billion soft Xray photons. These data were first processed using the standard NICER analysis pipeline. Then the arrival times of the X-ray photons were referred to the solar system's barycenter. Then specific analysis was done to study the specific behavior outlined in the following sections, while taking dead time into account. Results. The variation of the rotation frequency of the Crab pulsar and its time derivative during the glitch is almost exactly similar at the radio and X-ray energies. The following properties of the Crab pulsar remain essentially constant before and after the glitch: the total X-ray flux; the flux, widths, and peaks of the two components of its integrated profile; and the soft X-ray spectrum. There is no evidence for giant pulses at X-ray energies. However, the timing noise of the Crab pulsar shows quasi sinusoidal variation before the glitch, with increasing amplitude, which is absent after the glitch. Conclusions. Even the strongest glitch in the Crab pulsar appears not to affect all but one of the properties mentioned above, at either frequency. The fact that the timing noise appears to change due to the glitch is an important clue to unravel as this is still an unexplained phenomenon.

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Section: Parametersupporting

confidence: 66%

Section: Parametermentioning

confidence: 62%

Section: Observations and Analysismentioning

confidence: 99%

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NICER observations of the Crab pulsar glitch of 2017 November

Vivekanand¹

2020

A&A

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“…This however has to be extrapolated to the convectively stable radiative regions of the atmosphere where a number of complex processes such as gravity waves and convective overshooting (Freytag et al 1996;Kupka et al 2018) may drive the mixing. The value of K zz has also been approximated from 3D numerical simulations of hot Jupiters including passive tracer transport (Parmentier et al 2013;Zhang & Showman 2018b). These approaches to estimating K zz have their limitations and none has provided a quantitative picture that has reached a consensus in the community.…”

Section: Chemistry Schemesmentioning

confidence: 99%

A new set of atmosphere and evolution models for cool T–Y brown dwarfs and giant exoplanets

Phillips

Tremblin

Baraffe

et al. 2020

A&A

193

262

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We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs and self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere models are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, and are used as surface boundary conditions to calculate the interior structure and evolution of 0.001 − 0.075 M objects. Our models include several key improvements to the input physics used in previous models available in the literature. Most notably, the use of a new H-He equation of state including ab initio quantum molecular dynamics calculations has raised the mass by ∼ 1 − 2% at the stellar-substellar boundary and has altered the cooling tracks around the hydrogen and deuterium burning minimum masses. A second key improvement concerns updated molecular opacities in our atmosphere model ATMO, which now contains significantly more line transitions required to accurately capture the opacity in these hot atmospheres. This leads to warmer atmospheric temperature structures, further changing the cooling curves and predicted emission spectra of substellar objects. We present significant improvement for the treatment of the collisionally broadened potassium resonance doublet, and highlight the importance of these lines in shaping the red-optical and near-infrared spectrum of brown dwarfs. We generate three different grids of model simulations, one using equilibrium chemistry and two using non-equilibrium chemistry due to vertical mixing, all three computed self-consistently with the pressure-temperature structure of the atmosphere. We show the impact of vertical mixing on emission spectra and in colourmagnitude diagrams, highlighting how the 3.5 − 5.5 µm flux window can be used to calibrate vertical mixing in cool T-Y spectral type objects.

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“…This irradiation leads to a slight increase in the radius relative to non-irradiated models, but when implemented in 1D structure models cannot explain the radius inflation of many hot Jupiters (Arras & Bildsten 2006, Fortney et al 2007). Irradiation powers atmospheric circulation that acts to transport heat both from day-to-night (Perez-Becker & Showman 2013, Komacek & Showman 2016) and vertically (Youdin & Mitchell 2010, Tremblin et al 2017, Zhang & Showman 2018, Komacek et al 2019, Sainsbury-Martinez et al 2019, but this is not included in our modeling framework. We model deposited heating as an additional term in the extra energy dissipation rate extra , as was done in previous studies of gaseous planet evolution with MESA (Wu & Lithwick 2013, Komacek & Youdin 2017, Millholland 2019.…”

Section: Numerical Modelmentioning

confidence: 99%

Reinflation of Warm and Hot Jupiters

Komacek

Thorngren

Lopez

et al. 2020

ApJ

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Understanding the anomalous radii of many transiting hot gas giant planets is a fundamental problem of planetary science. Recent detections of re-inflated warm Jupiters orbiting post-main-sequence stars and the re-inflation of hot Jupiters while their host stars evolve on the main-sequence may help constrain models for the anomalous radii of hot Jupiters. In this work, we present evolution models studying the re-inflation of gas giants to determine how varying the depth and intensity of deposited heating affects both main-sequence re-inflation of hot Jupiters and post-main-sequence re-inflation of warm Jupiters. We find that deeper heating is required to re-inflate hot Jupiters than is needed to suppress their cooling, and that the timescale of re-inflation decreases with increasing heating rate and depth. We find a strong degeneracy between heating rate and depth, with either strong shallow heating or weak deep heating providing an explanation for main-sequence re-inflation of hot Jupiters. This degeneracy between heating rate and depth can be broken in the case of post-main-sequence re-inflation of warm Jupiters, as the inflation must be rapid to occur within post-main-sequence evolution timescales. We also show that the dependence of heating rate on incident stellar flux inferred from the sample of hot Jupiters can explain re-inflation of both warm and hot Jupiters. TESS will obtain a large sample of warm Jupiters orbiting post-main-sequence stars, which will help to constrain the mechanism(s) causing the anomalous radii of gas giant planets.

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X-Ray Observation of the 2017 November Glitch in the Crab Pulsar

Cited by 15 publications

References 13 publications

NICER observations of the Crab pulsar glitch of 2017 November

NICER observations of the Crab pulsar glitch of 2017 November

A new set of atmosphere and evolution models for cool T–Y brown dwarfs and giant exoplanets

Reinflation of Warm and Hot Jupiters

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